In recent years, various techniques for increasing recording capacity of a magnetic disk device have been developed. As one of these techniques, there is a recording technique called shingled write magnetic recording (SMR) or shingled write recording (SWR). When writing data to a magnetic disk, a shingled write type magnetic disk device writes the next recording track while overlapping a part of an adjacent track (hereinafter, referred to as adjacent track). In the shingled write type magnetic disk device, the width of overwritten tracks may be narrower than the width of tracks not overwritten.